# -*- coding: utf-8 -*-

# This program is free software: you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation, either version 3 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program.  If not, see <http://www.gnu.org/licenses/>.

"""

kallithea.model.scm

~~~~~~~~~~~~~~~~~~~

Scm model for Kallithea

This file was forked by the Kallithea project in July 2014.

Original author and date, and relevant copyright and licensing information is below:

:created_on: Apr 9, 2010

:author: marcink

:copyright: (c) 2013 RhodeCode GmbH, and others.

:license: GPLv3, see LICENSE.md for more details.

"""

import cStringIO

import logging

import os

import posixpath

import re

import sys

import traceback

import pkg_resources

from tg.i18n import ugettext as _

import kallithea

from kallithea import BACKENDS

from kallithea.lib.auth import HasPermissionAny, HasRepoGroupPermissionLevel, HasRepoPermissionLevel, HasUserGroupPermissionLevel

from kallithea.lib.exceptions import IMCCommitError, NonRelativePathError

from kallithea.lib.hooks import process_pushed_raw_ids

from kallithea.lib.utils import action_logger, get_filesystem_repos, make_ui

from kallithea.lib.utils2 import safe_str, safe_unicode, set_hook_environment

from kallithea.lib.vcs import get_backend

from kallithea.lib.vcs.backends.base import EmptyChangeset

from kallithea.lib.vcs.exceptions import RepositoryError

from kallithea.lib.vcs.nodes import FileNode

from kallithea.lib.vcs.utils.lazy import LazyProperty

from kallithea.model.db import PullRequest, RepoGroup, Repository, Session, Ui, User, UserFollowing, UserLog

log = logging.getLogger(__name__)

class UserTemp(object):

    def __init__(self, user_id):

        self.user_id = user_id

    def __repr__(self):

        return "<%s('id:%s')>" % (self.__class__.__name__, self.user_id)

class RepoTemp(object):

    def __init__(self, repo_id):

        self.repo_id = repo_id

    def __repr__(self):

        return "<%s('id:%s')>" % (self.__class__.__name__, self.repo_id)

class _PermCheckIterator(object):

    def __init__(self, obj_list, obj_attr, perm_set, perm_checker, extra_kwargs=None):

        """

        Creates iterator from given list of objects, additionally

        checking permission for them from perm_set var

        :param obj_list: list of db objects

        :param obj_attr: attribute of object to pass into perm_checker

        :param perm_set: list of permissions to check

        :param perm_checker: callable to check permissions against

        """

        self.obj_list = obj_list

        self.obj_attr = obj_attr

        self.perm_set = perm_set

        self.perm_checker = perm_checker

        self.extra_kwargs = extra_kwargs or {}

    def __len__(self):

        return len(self.obj_list)

    def __repr__(self):

        return '<%s (%s)>' % (self.__class__.__name__, self.__len__())

    def __iter__(self):

        for db_obj in self.obj_list:

            # check permission at this level

            name = getattr(db_obj, self.obj_attr, None)

            if not self.perm_checker(*self.perm_set)(

                    name, self.__class__.__name__, **self.extra_kwargs):

                continue

            yield db_obj

class RepoList(_PermCheckIterator):

    def __init__(self, db_repo_list, perm_level, extra_kwargs=None):

        super(RepoList, self).__init__(obj_list=db_repo_list,

                    obj_attr='repo_name', perm_set=[perm_level],

                    perm_checker=HasRepoPermissionLevel,

                    extra_kwargs=extra_kwargs)

class RepoGroupList(_PermCheckIterator):

    def __init__(self, db_repo_group_list, perm_level, extra_kwargs=None):

        super(RepoGroupList, self).__init__(obj_list=db_repo_group_list,

                    obj_attr='group_name', perm_set=[perm_level],

                    perm_checker=HasRepoGroupPermissionLevel,

                    extra_kwargs=extra_kwargs)

class UserGroupList(_PermCheckIterator):

    def __init__(self, db_user_group_list, perm_level, extra_kwargs=None):

        super(UserGroupList, self).__init__(obj_list=db_user_group_list,

                    obj_attr='users_group_name', perm_set=[perm_level],

                    perm_checker=HasUserGroupPermissionLevel,

                    extra_kwargs=extra_kwargs)

class ScmModel(object):

    """

    Generic Scm Model

    """

    def __get_repo(self, instance):

        cls = Repository

        if isinstance(instance, cls):

            return instance

        elif isinstance(instance, int) or safe_str(instance).isdigit():

            return cls.get(instance)

        elif isinstance(instance, basestring):

            return cls.get_by_repo_name(instance)

        elif instance is not None:

            raise Exception('given object must be int, basestr or Instance'

                            ' of %s got %s' % (type(cls), type(instance)))

    @LazyProperty

    def repos_path(self):

        """

        Gets the repositories root path from database

        """

        q = Ui.query().filter(Ui.ui_key == '/').one()

        return q.ui_value

    def repo_scan(self, repos_path=None):

        """

        Listing of repositories in given path. This path should not be a

        repository itself. Return a dictionary of repository objects

        :param repos_path: path to directory containing repositories

        """

        if repos_path is None:

            repos_path = self.repos_path

        log.info('scanning for repositories in %s', repos_path)

        baseui = make_ui()

        repos = {}

        for name, path in get_filesystem_repos(repos_path):

            # name need to be decomposed and put back together using the /

            # since this is internal storage separator for kallithea

            name = Repository.normalize_repo_name(name)

            try:

                if name in repos:

                    raise RepositoryError('Duplicate repository name %s '

                                          'found in %s' % (name, path))

                else:

                    klass = get_backend(path[0])

                    if path[0] == 'hg' and path[0] in BACKENDS.keys():

                        repos[name] = klass(safe_str(path[1]), baseui=baseui)

                    if path[0] == 'git' and path[0] in BACKENDS.keys():

                        repos[name] = klass(path[1])

            except OSError:

                continue

        log.debug('found %s paths with repositories', len(repos))

        return repos

    def get_repos(self, repos):

        """Return the repos the user has access to"""

        return RepoList(repos, perm_level='read')

    def get_repo_groups(self, groups=None):

        """Return the repo groups the user has access to

        If no groups are specified, use top level groups.

        """

        if groups is None:

            groups = RepoGroup.query() \

                .filter(RepoGroup.parent_group_id == None).all()

        return RepoGroupList(groups, perm_level='read')

    def mark_for_invalidation(self, repo_name):

        """

        Mark caches of this repo invalid in the database.

        :param repo_name: the repo for which caches should be marked invalid

        """

        log.debug("Marking %s as invalidated and update cache", repo_name)

        repo = Repository.get_by_repo_name(repo_name)

        if repo is not None:

            repo.set_invalidate()

            repo.update_changeset_cache()

    def toggle_following_repo(self, follow_repo_id, user_id):

        f = UserFollowing.query() \

            .filter(UserFollowing.follows_repository_id == follow_repo_id) \

            .filter(UserFollowing.user_id == user_id).scalar()

        if f is not None:

            try:

                Session().delete(f)

                action_logger(UserTemp(user_id),

                              'stopped_following_repo',

                              RepoTemp(follow_repo_id))

                return

            except Exception:

                log.error(traceback.format_exc())

                raise

        try:

            f = UserFollowing()

            f.user_id = user_id

            f.follows_repository_id = follow_repo_id

            Session().add(f)

            action_logger(UserTemp(user_id),

                          'started_following_repo',

                          RepoTemp(follow_repo_id))

        except Exception:

            log.error(traceback.format_exc())

            raise

    def toggle_following_user(self, follow_user_id, user_id):

        f = UserFollowing.query() \

            .filter(UserFollowing.follows_user_id == follow_user_id) \

            .filter(UserFollowing.user_id == user_id).scalar()

        if f is not None:

            try:

                Session().delete(f)

                return

            except Exception:

                log.error(traceback.format_exc())

                raise

        try:

            f = UserFollowing()

            f.user_id = user_id

            f.follows_user_id = follow_user_id

            Session().add(f)

        except Exception:

            log.error(traceback.format_exc())

            raise

        r = Repository.query() \

            .filter(Repository.repo_name == repo_name).scalar()

        f = UserFollowing.query() \

            .filter(UserFollowing.follows_repository == r) \

            .filter(UserFollowing.user_id == user_id).scalar()

        return f is not None

        u = User.get_by_username(username)

        f = UserFollowing.query() \

            .filter(UserFollowing.follows_user == u) \

            .filter(UserFollowing.user_id == user_id).scalar()

        return f is not None

    def get_followers(self, repo):

        repo = Repository.guess_instance(repo)

        return UserFollowing.query() \

                .filter(UserFollowing.follows_repository == repo).count()

    def get_forks(self, repo):

        repo = Repository.guess_instance(repo)

        return Repository.query() \

                .filter(Repository.fork == repo).count()

    def get_pull_requests(self, repo):

        repo = Repository.guess_instance(repo)

        return PullRequest.query() \

                .filter(PullRequest.other_repo == repo) \

                .filter(PullRequest.status != PullRequest.STATUS_CLOSED).count()

    def mark_as_fork(self, repo, fork, user):

        repo = self.__get_repo(repo)

        fork = self.__get_repo(fork)

        if fork and repo.repo_id == fork.repo_id:

            raise Exception("Cannot set repository as fork of itself")

        if fork and repo.repo_type != fork.repo_type:

            raise RepositoryError("Cannot set repository as fork of repository with other type")

        repo.fork = fork

        return repo

    def _handle_push(self, repo, username, ip_addr, action, repo_name, revisions):

        """

        Handle that the repository has changed.

        Adds an action log entry with the new revisions, and the head revision

        cache and in-memory caches are invalidated/updated.

        :param username: username who pushes

        :param action: push/push_local/push_remote

        :param repo_name: name of repo

        :param revisions: list of revisions that we pushed

        """

        set_hook_environment(username, ip_addr, repo_name, repo_alias=repo.alias, action=action)

        process_pushed_raw_ids(revisions) # also calls mark_for_invalidation

    def _get_IMC_module(self, scm_type):

        """

        Returns InMemoryCommit class based on scm_type

        :param scm_type:

        """

        if scm_type == 'hg':

            from kallithea.lib.vcs.backends.hg import MercurialInMemoryChangeset

            return MercurialInMemoryChangeset

        if scm_type == 'git':

            from kallithea.lib.vcs.backends.git import GitInMemoryChangeset

            return GitInMemoryChangeset

        raise Exception('Invalid scm_type, must be one of hg,git got %s'

                        % (scm_type,))

    def pull_changes(self, repo, username, ip_addr, clone_uri=None):

        """

        Pull from "clone URL" or fork origin.

        """

        dbrepo = self.__get_repo(repo)

        if clone_uri is None:

            clone_uri = dbrepo.clone_uri or dbrepo.fork and dbrepo.fork.repo_full_path

        if not clone_uri:

            raise Exception("This repository doesn't have a clone uri")

        repo = dbrepo.scm_instance

        repo_name = dbrepo.repo_name

        try:

            if repo.alias == 'git':

                repo.fetch(clone_uri)

                # git doesn't really have something like post-fetch action

                # we fake that now.

                # TODO: extract fetched revisions ... somehow ...

                self._handle_push(repo,

                                  username=username,

                                  ip_addr=ip_addr,

                                  action='push_remote',

                                  repo_name=repo_name,

                                  revisions=[])

            else:

                set_hook_environment(username, ip_addr, dbrepo.repo_name,

                                           repo.alias, action='push_remote')

                repo.pull(clone_uri)

        except Exception:

            log.error(traceback.format_exc())

            raise

    def commit_change(self, repo, repo_name, cs, user, ip_addr, author, message,

                      content, f_path):

        """

        Commit a change to a single file

        :param repo: a db_repo.scm_instance

        """

        user = User.guess_instance(user)

        IMC = self._get_IMC_module(repo.alias)

        # decoding here will force that we have proper encoded values

        # in any other case this will throw exceptions and deny commit

        content = safe_str(content)

        path = safe_str(f_path)

        # message and author needs to be unicode

        # proper backend should then translate that into required type

        message = safe_unicode(message)

        author = safe_unicode(author)

        imc = IMC(repo)

        imc.change(FileNode(path, content, mode=cs.get_file_mode(f_path)))

        try:

            tip = imc.commit(message=message, author=author,

                             parents=[cs], branch=cs.branch)

        except Exception as e:

            log.error(traceback.format_exc())

            # clear caches - we also want a fresh object if commit fails

            self.mark_for_invalidation(repo_name)

            raise IMCCommitError(str(e))

        self._handle_push(repo,

                          username=user.username,

                          ip_addr=ip_addr,

                          action='push_local',

                          repo_name=repo_name,

                          revisions=[tip.raw_id])

        return tip

    def _sanitize_path(self, f_path):

        if f_path.startswith('/') or f_path.startswith('.') or '../' in f_path:

            raise NonRelativePathError('%s is not an relative path' % f_path)

        if f_path:

            f_path = posixpath.normpath(f_path)

        return f_path

    def get_nodes(self, repo_name, revision, root_path='/', flat=True):

        """

        Recursively walk root dir and return a set of all paths found.

        :param repo_name: name of repository

        :param revision: revision for which to list nodes

        :param root_path: root path to list

        :param flat: return as a list, if False returns a dict with description

        """

        _files = list()

        _dirs = list()

        try:

            _repo = self.__get_repo(repo_name)

            changeset = _repo.scm_instance.get_changeset(revision)

            root_path = root_path.lstrip('/')

            for topnode, dirs, files in changeset.walk(root_path):

                for f in files:

                    _files.append(f.path if flat else {"name": f.path,

                                                       "type": "file"})

                for d in dirs:

                    _dirs.append(d.path if flat else {"name": d.path,

                                                      "type": "dir"})

        except RepositoryError:

            log.debug(traceback.format_exc())

            raise

        return _dirs, _files

    def create_nodes(self, user, ip_addr, repo, message, nodes, parent_cs=None,

                     author=None, trigger_push_hook=True):

        """

        Commits specified nodes to repo.

        :param user: Kallithea User object or user_id, the committer

        :param repo: Kallithea Repository object

        :param message: commit message

        :param nodes: mapping {filename:{'content':content},...}

        :param parent_cs: parent changeset, can be empty than it's initial commit

        :param author: author of commit, cna be different that committer only for git

        :param trigger_push_hook: trigger push hooks

        :returns: new committed changeset

        """

        user = User.guess_instance(user)

        scm_instance = repo.scm_instance_no_cache()

        processed_nodes = []

        for f_path in nodes:

            content = nodes[f_path]['content']

            f_path = self._sanitize_path(f_path)

            f_path = safe_str(f_path)

            # decoding here will force that we have proper encoded values

            # in any other case this will throw exceptions and deny commit

            if isinstance(content, (basestring,)):

                content = safe_str(content)

            elif isinstance(content, (file, cStringIO.OutputType,)):

                content = content.read()

            else:

                raise Exception('Content is of unrecognized type %s' % (

                    type(content)

                ))

            processed_nodes.append((f_path, content))

        message = safe_unicode(message)

        committer = user.full_contact

        author = safe_unicode(author) if author else committer

        IMC = self._get_IMC_module(scm_instance.alias)

        imc = IMC(scm_instance)

        if not parent_cs:

            parent_cs = EmptyChangeset(alias=scm_instance.alias)

        if isinstance(parent_cs, EmptyChangeset):

            # EmptyChangeset means we we're editing empty repository

            parents = None

        else:

            parents = [parent_cs]

        # add multiple nodes

        for path, content in processed_nodes:

            imc.add(FileNode(path, content=content))

        tip = imc.commit(message=message,

                         author=author,

                         parents=parents,

                         branch=parent_cs.branch)

        if trigger_push_hook:

            self._handle_push(scm_instance,

                              username=user.username,

                              ip_addr=ip_addr,

                              action='push_local',

                              repo_name=repo.repo_name,

                              revisions=[tip.raw_id])

        else:

            self.mark_for_invalidation(repo.repo_name)

        return tip

    def update_nodes(self, user, ip_addr, repo, message, nodes, parent_cs=None,

                     author=None, trigger_push_hook=True):

        """

        Commits specified nodes to repo. Again.

        """

        user = User.guess_instance(user)

        scm_instance = repo.scm_instance_no_cache()

        message = safe_unicode(message)

        committer = user.full_contact

        author = safe_unicode(author) if author else committer

        imc_class = self._get_IMC_module(scm_instance.alias)

        imc = imc_class(scm_instance)

        if not parent_cs:

            parent_cs = EmptyChangeset(alias=scm_instance.alias)

        if isinstance(parent_cs, EmptyChangeset):

            # EmptyChangeset means we we're editing empty repository

            parents = None

        else:

            parents = [parent_cs]

        # add multiple nodes

        for _filename, data in nodes.items():

            # new filename, can be renamed from the old one

            filename = self._sanitize_path(data['filename'])

            old_filename = self._sanitize_path(_filename)

            content = data['content']

            filenode = FileNode(old_filename, content=content)

            op = data['op']

            if op == 'add':

                imc.add(filenode)

            elif op == 'del':

                imc.remove(filenode)

            elif op == 'mod':

                if filename != old_filename:

                    # TODO: handle renames, needs vcs lib changes

                    imc.remove(filenode)

                    imc.add(FileNode(filename, content=content))

                else:

                    imc.change(filenode)

        # commit changes

        tip = imc.commit(message=message,

                         author=author,

                         parents=parents,

                         branch=parent_cs.branch)

        if trigger_push_hook:

            self._handle_push(scm_instance,

                              username=user.username,

                              ip_addr=ip_addr,

                              action='push_local',

                              repo_name=repo.repo_name,

                              revisions=[tip.raw_id])

        else:

            self.mark_for_invalidation(repo.repo_name)

    def delete_nodes(self, user, ip_addr, repo, message, nodes, parent_cs=None,

                     author=None, trigger_push_hook=True):

        """

        Deletes specified nodes from repo.

        :param user: Kallithea User object or user_id, the committer

        :param repo: Kallithea Repository object

        :param message: commit message

        :param nodes: mapping {filename:{'content':content},...}

        :param parent_cs: parent changeset, can be empty than it's initial commit

        :param author: author of commit, cna be different that committer only for git

        :param trigger_push_hook: trigger push hooks

        :returns: new committed changeset after deletion

        """

        user = User.guess_instance(user)

        scm_instance = repo.scm_instance_no_cache()

        processed_nodes = []

        for f_path in nodes:

            f_path = self._sanitize_path(f_path)

            # content can be empty but for compatibility it allows same dicts

            # structure as add_nodes

            content = nodes[f_path].get('content')

            processed_nodes.append((f_path, content))

        message = safe_unicode(message)

        committer = user.full_contact

        author = safe_unicode(author) if author else committer

        IMC = self._get_IMC_module(scm_instance.alias)

        imc = IMC(scm_instance)

        if not parent_cs:

            parent_cs = EmptyChangeset(alias=scm_instance.alias)

        if isinstance(parent_cs, EmptyChangeset):

            # EmptyChangeset means we we're editing empty repository

            parents = None

        else:

            parents = [parent_cs]

        # add multiple nodes

        for path, content in processed_nodes:

            imc.remove(FileNode(path, content=content))

        tip = imc.commit(message=message,

                         author=author,

                         parents=parents,

                         branch=parent_cs.branch)

        if trigger_push_hook:

            self._handle_push(scm_instance,

                              username=user.username,

                              ip_addr=ip_addr,

                              action='push_local',

                              repo_name=repo.repo_name,

                              revisions=[tip.raw_id])

        else:

            self.mark_for_invalidation(repo.repo_name)

        return tip

    def get_unread_journal(self):

        return UserLog.query().count()

    def get_repo_landing_revs(self, repo=None):

        """

        Generates select option with tags branches and bookmarks (for hg only)

        grouped by type

        :param repo:

        """

        hist_l = []

        choices = []

        repo = self.__get_repo(repo)

        hist_l.append(('rev:tip', _('latest tip')))

        choices.append('rev:tip')

        if repo is None:

            return choices, hist_l

# -*- coding: utf-8 -*-

# This program is free software: you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation, either version 3 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program.  If not, see <http://www.gnu.org/licenses/>.

"""

kallithea.model.user_group

~~~~~~~~~~~~~~~~~~~~~~~~~~

user group model for Kallithea

This file was forked by the Kallithea project in July 2014.

Original author and date, and relevant copyright and licensing information is below:

:created_on: Oct 1, 2011

:author: nvinot, marcink

"""

import logging

import traceback

from kallithea.lib.exceptions import RepoGroupAssignmentError, UserGroupsAssignedException

from kallithea.model.db import (

    Permission, Session, User, UserGroup, UserGroupMember, UserGroupRepoToPerm, UserGroupToPerm, UserGroupUserGroupToPerm, UserUserGroupToPerm)

log = logging.getLogger(__name__)

class UserGroupModel(object):

    def _create_default_perms(self, user_group):

        # create default permission

        default_perm = 'usergroup.read'

        def_user = User.get_default_user()

        for p in def_user.user_perms:

            if p.permission.permission_name.startswith('usergroup.'):

                default_perm = p.permission.permission_name

                break

        user_group_to_perm = UserUserGroupToPerm()

        user_group_to_perm.permission = Permission.get_by_key(default_perm)

        user_group_to_perm.user_group = user_group

        user_group_to_perm.user_id = def_user.user_id

        Session().add(user_group_to_perm)

        return user_group_to_perm

    def _update_permissions(self, user_group, perms_new=None,

                            perms_updates=None):

        from kallithea.lib.auth import HasUserGroupPermissionLevel

        if not perms_new:

            perms_new = []

        if not perms_updates:

            perms_updates = []

        # update permissions

        for member, perm, member_type in perms_updates:

            if member_type == 'user':

                # this updates existing one

                self.grant_user_permission(

                    user_group=user_group, user=member, perm=perm

                )

            else:

                # check if we have permissions to alter this usergroup's access

                if HasUserGroupPermissionLevel('read')(member):

                    self.grant_user_group_permission(

                        target_user_group=user_group, user_group=member, perm=perm

                    )

        # set new permissions

        for member, perm, member_type in perms_new:

            if member_type == 'user':

                self.grant_user_permission(

                    user_group=user_group, user=member, perm=perm

                )

            else:

                # check if we have permissions to alter this usergroup's access

                if HasUserGroupPermissionLevel('read')(member):

                    self.grant_user_group_permission(

                        target_user_group=user_group, user_group=member, perm=perm

                    )

        return UserGroup.get(user_group_id)

    def get_group(self, user_group):

        return UserGroup.guess_instance(user_group)

    def get_by_name(self, name, cache=False, case_insensitive=False):

        return UserGroup.get_by_group_name(name, cache=cache, case_insensitive=case_insensitive)

    def create(self, name, description, owner, active=True, group_data=None):

        try:

            new_user_group = UserGroup()

            new_user_group.owner = User.guess_instance(owner)

            new_user_group.users_group_name = name

            new_user_group.user_group_description = description

            new_user_group.users_group_active = active

            if group_data:

                new_user_group.group_data = group_data

            Session().add(new_user_group)

            self._create_default_perms(new_user_group)

            self.grant_user_permission(user_group=new_user_group,

                                       user=owner, perm='usergroup.admin')

            return new_user_group

        except Exception:

            log.error(traceback.format_exc())

            raise

    def update(self, user_group, form_data):

        try:

            user_group = UserGroup.guess_instance(user_group)

            for k, v in form_data.items():

                if k == 'users_group_members':

                    members_list = []

                    if v:

                        v = [v] if isinstance(v, basestring) else v

                        for u_id in set(v):

                            member = UserGroupMember(user_group.users_group_id, u_id)

                            members_list.append(member)

                            Session().add(member)

                    user_group.members = members_list

                setattr(user_group, k, v)

            # Flush to make db assign users_group_member_id to newly

            # created UserGroupMembers.

            Session().flush()

        except Exception:

            log.error(traceback.format_exc())

            raise

    def delete(self, user_group, force=False):

        """

        Deletes user group, unless force flag is used

        raises exception if there are members in that group, else deletes

        group and users

        :param user_group:

        :param force:

        """

        user_group = UserGroup.guess_instance(user_group)

        try:

            # check if this group is not assigned to repo

            assigned_groups = UserGroupRepoToPerm.query() \

                .filter(UserGroupRepoToPerm.users_group == user_group).all()

            assigned_groups = [x.repository.repo_name for x in assigned_groups]

            if assigned_groups and not force:

                raise UserGroupsAssignedException(

                    'User Group assigned to %s' % ", ".join(assigned_groups))

            Session().delete(user_group)

        except Exception:

            log.error(traceback.format_exc())

            raise

    def add_user_to_group(self, user_group, user):

        """Return True if user already is in the group - else return the new UserGroupMember"""

        user_group = UserGroup.guess_instance(user_group)

        user = User.guess_instance(user)

        for m in user_group.members:

            u = m.user

            if u.user_id == user.user_id:

                # user already in the group, skip

                return True

        try:

            user_group_member = UserGroupMember()

            user_group_member.user = user

            user_group_member.users_group = user_group

            user_group.members.append(user_group_member)

            user.group_member.append(user_group_member)

            Session().add(user_group_member)

            return user_group_member

        except Exception:

            log.error(traceback.format_exc())

            raise

    def remove_user_from_group(self, user_group, user):

        user_group = UserGroup.guess_instance(user_group)

        user = User.guess_instance(user)

        user_group_member = None

        for m in user_group.members:

            if m.user_id == user.user_id:

                # Found this user's membership row